Propagate writeStrict port option to RemoteCotrolBoard

yarp port has the writeStrict option but was not possible to tell RemoteControlBoard to activate it if necessary.
The configuration now checks also for a 'writeStrict' option with 'on' or 'off' as possible choises where 'off' is the default (keep backward behaviour).
This happened to be needed for streaming port because otherwise some commands were sistematically lost.
fix typo
add (optional) api call to commit to a single port type
helper for sending non-terminated strings with lengths
do not mix terminator ports and topics
add yarp/image type information to framegrabber server
fix transmission of images from YARP to ROS
preconnect subscriber when running over roscore
do initial ros subscriber hookups in a separate thread
xmlrpc connections against ros are terminated on receiver side
fix stray RF log message that does not respect --verbose false
use deprecated-old-style-context only when a policy is set [thanks elen4]
Adding yarp_install_copy target to force copy to the build tree of files/directories added with the yarp_install command
Changed yarp_install macro parsing & use of arguments